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Results for “Hypophysectomy”

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PubMed1980

[Effect of hypophysectomy on neutrophilopoiesis].

The bone marrow of hypophysectomized rats exposed to irradiation with a dose of 400 C/kg or 6-hour immobilization has been studied. It has been found that hypophysectomy itself does not affect neutrophilopoiesis since its insufficiency is revealed only on the body exposure to additional loadings (irradiation or immobilization). This was manifested in the suppression of postradiative regeneration of neutrophilopoiesis and in the lack of granulocytopoiesis activation over a period of 24-48 h after the commencement of 6-hour immobilization.

Animals↗
PubMed1980

[Peroperative hyperthermia in chemical hypophysectomies].

In this work the Authors enunciate various physiopathogenetic hypotheses about malignant hyperthermia occurring in general anaesthesia for chemical-hypophysectomy: serotoninergic system would induce malignant hyperpyrexia? This is the most probable hypothesis.

Body Temperature Regulation↗
PubMed1994

Acromegaly and transsphenoidal hypophysectomy: a case report.

Anterior pituitary tumors account for nearly 18% of all intracranial tumors. Pituitary adenomas that cause hypersecretion of growth hormone lead to acromegaly in adults. Patients with acromegaly may present unique problems for the anesthetist because of the overgrowth of airway soft tissues; a difficult mask ventilation and challenging intubation can be expected. A careful preoperative assessment of the patient's airway is essential, and an awake oral or fiberoptic bronchoscopy may be necessary. Postoperatively, these patients are at risk for developing airway problems and diabetes insipidus; therefore, they warrant careful observation. A 42-year-old, 75-kg, ASA physical status III, white male presented 8 months after suffering a head injury in which he was knocked unconscious for approximately 3 minutes. He began experiencing severe headaches, visual changes, and a marked increase in the size of his hands and feet. Four months before admission, he underwent bilateral carpal tunnel repairs. The patient was diagnosed with acromegaly after an extensive endocrine and neurosurgical evaluation. This is a case report of a patient with acromegaly who underwent an elective transsphenoidal hypophysectomy.

Acromegaly↗
PubMed1976

[Hypophysectomy and androgen synthesis in rat embryos].

Hypophysectomy by decapitation of the rat embryo at the age of 16 days results in a lesser development of the testes when examined at 18 days. The synthesis levels of testosterone and androstenedione have been determined. When correlated with the mass of tissue, the values found for the synthesis levels were smaller in the decapitated embryos than in the normal ones. It is probable that the hypophysis is active in androgen synthesis in the rat embryo at a stage as early as 18 days.

Androgens↗
PubMed1993

[Exacerbation of autoimmune hypothyroidism after hemi-hypophysectomy in a patient with Cushing's disease].

A 41 year old woman affected by Cushing's disease underwent hemi-hypophysectomy with removal of an ACTH secreting microadenoma. Forty days later, when normal ACTH, cortisol plasma levels and urinary cortisol levels were restored, features of primary autoimmune hypothyroidism developed. While cortisol levels were elevated serum thyroid hormone levels were normal, serum hormone TSH was at the upper limit of the normal range and serum antimicrosomal antibodies were slightly elevated. It is likely that hypothyroidism already present before surgery was not clinically evident due to the immunosuppressive effect of high cortisol levels. The need to assess thyroid function in patient with hypercortisolism is emphasized with the aim to identify the possible onset of autoimmune thyroid disease when cortisol levels are normalized.

ACTH Syndrome, Ectopic↗
PubMed1976

[Course of thyroxinemia during the development of the chick embryo. Influence of hypophysectomy].

Plasma thyroxine (T4) level of intact and hypophysectomized Chick embryos has been determined for the incubation interval 10 to 18 days. T4, which is the main circulating thyroid hormone, exists as early as day 10. The plasma T4 level of controls increases as power function of time from day 10 to day 17. Hypophysectomy (on day 2) produces a decrease of the plasma T4 level, but only from day 11, which accounts for the beginning of a pituitary control of the thyroid secretion after day 10.

Animals↗
PubMed1993

[A morphofunctional study of the hypothalamic postoptic nucleus after hypophysectomy, cooling and immobilization in rats].

Response of the vasopressin (VP) and oxytocin (OT) cells of hypothalamic post optical nucleus (PON) was studied in male Wistar rats under various experimental conditions. Seven days after hypophysectomy, the majority of both VP- and OT-cells became pyknomorphic which seemed to be the result of transsection of the PON-cell axons and indicated that the PON-cells released neurohormones from the posterior pituitary into the blood. When rats were cooled (2 h at 4 degrees C), the size of nucleoli in VP-cells diminished significantly, but in rats stressed by severe immobilization (20 min) these cells revealed clear signs of activation. In contrast to that, no changes were observed in the OT-cells after these treatments. The functional relation of the PON and thyroid gland is discussed.

Animals↗
PubMed1995

Influence of age and fetal hypophysectomy on porcine preadipocytes: insulin-like growth factor-I (IGF-I) response, receptor binding and IGF binding proteins secretion.

The effects of fetal hypophysectomy (hypox) and age on insulin-like growth factor-I (IGF-I) response, receptor binding and IGF-I & IGF binding protein secretion by porcine preadipocytes was examined. Primary cultures of stromal vascular (S-V) cells derived from fetal and postnatal adipose tissue were established and exposed to test media (different concentrations of pig serum with or without IGF-I) for morphological study or to serum-free media for measuring IGF-I receptor binding and IGF-I & IGFBPs secretion. Conditioned media were collected and subjected to IGF-I RIA and ligand blot and immunoblot analysis. IGF-I significantly stimulated total cell growth (determined by DNA levels) and increased fat cell cluster number and lipid deposition in porcine S-V cultures (determined by image analysis). Although the pattern of response to IGF-I was similar in fetal and postnatal cultures, the response was greater in fetal cultures. The mitogenic and adipogenic response of fetal preadipocytes to IGF-I was impaired by fetal hypox. Specific IGF-I binding sites on fetal preadipocytes had a higher binding affinity for IGF-I (Kd = 2.82 +/- 0.28 nM) than did postnatal preadipocytes (Kd = 7.28 +/- 1.52 nM, P < 0.05). Preadipocytes secreted IGF-I and four IGF-BPs (BP-1, -2, -3, and -4) in a developmentally regulated manner. For example, IGFBP-2, and -3 were predominant binding proteins secreted by fetal preadipocytes which represented 47% and 30% of the total, respectively. IGFBP-1 was the major binding protein secreted by postnatal preadipocytes. Furthermore, fetal cells secreted greater amounts of IGF-I in cultures than did postnatal cells (2428 +/- 205 pg/ml vs. 870 +/- 31 pg/ml, P < 0.05). Fetal hypox caused a decrease from 47% to 68% of control values in all four IGFBPs secreted by preadipocytes. The changes in IGF-I receptor binding and IGF-I and IGFBP secretion by preadipocytes may account for altered response of preadipocytes to IGF-I. Thus, secretion of IGF-I and IGFBPs, IGF-I binding and response of porcine preadipocytes were affected by age and fetal hypox. The results indicated that locally produced IGF-I and IGFBPs may play a critical paracrine/autocrine role during fetal adipose development.

Adipose Tissue↗
PubMed1977

Effects of hypophysectomy, pituitary gland homogenates and transplants, and prolactin on photoreceptor destruction.

Prepubertal removal of the pituitary gland, which in young animals influences sexual maturation, reduces significantly the amount of retinal photoreceptor destruction when the rats are exposed to continuous illumination in adulthood. When crude pituitary gland homogenate is administered to adult rats hypophysectomized prior to puberty, photoreceptor destruction is more severe. Transplantation of whole pituitary glands to the kidney capsule of hypophysectomized rats also reduces the effect of pituitary gland removal and results in more extensive damage to receptor cells than found in hypophysectomized, adult animals. Hypophysectomized rats treated with prolactin had more severe retinal damage than untreated, hypophysectomized rats. The injection of pregnant mare serum and human chorionic gonadotropic hormones into hypophysectomized rats was not effective in reversing the protection afforded by hypophysectomy. Results of these studies indicate the hormones of the pituitary gland have a regulatory influence on the severity of light-induced, retinal photoreceptor damage in the rat.

Animals↗
PubMed1976

[Objectivation of psychic alterations in patients after hypophysectomy (author's transl)].

17 patients who had undergone transfrontal hypophysectomy were compared as regards their performance in the MMPI Saarbrücken and the Rosenzweig-Picture-Frustation Study with an equal number of patients who had undergone comparable head surgery. The results suggest that the psychic alterations revealed in these tests may be regarded as unspecific consequences of the operative method.

Adult↗
PubMed1976

Oral-contraceptive-induced hypertension after adrenalectomy and hypophysectomy.

The cause of oral-contraceptive-induced hypertension in certain susceptible subjects is obscure. We describe a woman who was receiving replacement doses of fludrocortisone acetate after adrenalectomy and hypophysectomy who developed high blood pressure while ingesting an estrogen-containing oral contraceptive. Renin substrate level was increased, but renin activity was suppressed and unresponsive to tilting. The patient developed a markedly exaggerated natriuresis when infused with saline. Both blood pressure and her responses to infused sodium and tilting normalized after discontinuance of the oral contraceptive medication. In this adrenalectomized patient, the estrogenic component of the pill acting synergistically with a fixed ("nonsuppressible") replacement dose of mineralocorticoid seems to have caused a volume-related hypertension.

Adenoma, Chromophobe↗
PubMedDate not supplied

Hormonal regulation of spermatogenesis in the hypophysectomized rat: quantitation of germ-cell population and effect of elimination of residual testosterone after long-term hypophysectomy.

Spermatogenesis continues after long-term hypophysectomy (Hx), but massive cell degeneration prevents seminiferous tubules from attaining the full complement of cells. One objective of this study was to determine the vulnerable sites for completion of spermatogenesis in long-term Hx rats. It is now known that Leydig cells continue to secrete small amounts of androgen after Hx. A second objective was to determine the cellular sites that are maintained by residual androgen secreted by Leydig cells post-Hx. Two groups of adult animals were utilized. Both groups were Hx for 36 days, but one group of rats received the androgen antagonist flutamide during the 26th through the 36th day of Hx (10 days). Germ-cell numbers were quantified using a method that allowed their expression as numbers of cells present per hour of development. In the long-term Hx rat, the germ-cell population increased to preleptotene, but the divisions that led to preleptotene were inefficient due to cell degeneration. Subsequent to preleptotene, there was a gradual loss in cells such that there were few germ cells remaining by steps 9-13. Flutamide given to Hx rats did not result in a significant difference in the numbers of intermediate and type B spermatogonia or significant differences in progenitor cells. A significant and major depression of cell numbers in Hx-flutamide-treated rats occurred in the cell division of type B spermatogonia to form preleptotene spermatocytes. There was a less dramatic, although significant, depression of cell numbers in Hx-flutamide-treated animals that occurred from preleptotene until late pachytene as well as an increased loss of round spermatids at midcycle (step 5-6). These data demonstrate that cell loss after long-term Hx occurs at numerous phases of spermatogenesis. The data also demonstrate that the presence of residual androgen action after long-term Hx results in enhanced germ-cell survival. Although the major blockage in cell viability occurs at midcycle steps in the long-term Hx rat, there are several other hormone-sensitive phases of spermatogenesis.

Androgen Antagonists↗
PubMed1998

[Endonasal sequelae after hypophysectomy].

Each year, 15 transvestibular transseptal transsphenoidal hypophysectomies are performed in Lausanne. The aim of the study was to determine the complications rate of our procedure and their influence on the life quality of patients. Questionnaires were sent to 178 patients, operated between 1984 and 1995. 125 questionnaires were returned. Out of those, 73 patients accepted to undergo a control rhinoscopy. The most frequent complains were nasal obstruction and crusting (38% each), whistling while breathing through the nose (12%), and stuffiness of the upper lip or teeth (7%). Endoscopically, we detected an anterior septal perforation in 10 cases (13.7%), 8 (80%) of which were symptomatic and a posterior septal perforation in 6 cases, all of them being asymptomatic. Finally, 36% of the patients had no complains and 19% of them had an improvement of respiration after the operation. Of the whole series of 178 patients, only 5% had complications requiring an ENT follow-up for longer than 6 months after having been operated.

Adolescent↗
PubMed1995

Failure of Partial Hypophysectomy as Definitive Treatment in Cushing's Disease Owing to Nodular Corticotrope Hyperplasia: Report of Four Cases.

Nodular corticotrope hyperplasia is a rare pathology causing Cushing's syndrome owing to a primary pituitary disease or ectopic CRH production. In this study, we evaluated the laboratory and pathological findings and results of transsphenoidal pituitary surgery in four patients with Cushing's disease. Dynamic tests of pituitary-adrenal function (dexamethasone suppression, metyrapone, CRH, and DDAVP tests) were done before and after transsphenoidal pituitary surgery. Plasma and total urinary cortisol, serum 11-deoxycortisol, and plasma ACTH were determined by RIA. Hormonal dynamic tests and radiologic studies were compatible with a pituitary ACTH source. The transsphenoidal surgery revealed the presence of corticotrope hyperplasia confirmed by immunoperoxidase stain and a preserved reticulum framework in the removed pituitary tissue of these four patients. The pituitary surgery led to a short period of improvement in two of the patients (1 and 4), a 3-yr remission in one patient (patient 2), and no improvement in one (patient 3). We conclude that although our patients appear to have inadequate suppression with high-dose dexamethasone, there is no way to diagnose this pathology presurgically, and that total hypophysectomy, bilateral adrenalectomy, and irradiation are the only alternatives for definitive treatment. A CRH-secreting ectopic tumor could not be found in our patients either before or after surgery in the follow-up period.

Journal Article↗
PubMed1980

The effect of hypophysectomy on acupuncture analgesia in the mouse.

Acupuncture analgesia was quantitated in the phenylquinone induced writhing test in mice. Both manual acupuncture and electroacupuncture significantly reduced the number of writhes, i.e. 47% and 51% reduction respectively. Naloxone (2 mg/kg) pretreatment abolished this antinocicpetive effect suggesting that an endogenous opiate-like substance was involved. Hypophysectomy did not alter the electroacupuncture induced inhibition of writhing. These results confirm previous reports that acupuncture causes the release of an endogenous substance(s) with opioid activity, but disagree with previous reports in that our data show that the hypophysis is not involved in the release of this endogenous opiate or in any other mechanism of acupuncture analgesia in the mouse.

Acupuncture Therapy↗
PubMed1983

The effect of hypophysectomy and gonadotropin administration on the distribution and quantity of LH-RH in the brains of platyfish: a combined immunocytochemistry and radioimmunoassay study.

Radioimmunoassay (RIA) and immunocytochemistry (ICC) were used to study the effect of hypophysectomy (H) on the distribution and quantity of luteinizing hormone-releasing hormone (LH-RH) in the brains of sham-operated-saline-injected, H-saline-injected and H-gonadotropin (GTH)-injected mature female platyfish (Xiphophorus maculatus). In fish hypophysectomized for 5 weeks, there was a decrease in the LH-RH content of the brain (mean +/- S.E. = 446 +/- 31 pg, H-saline-injected; 649 +/- 28 pg, sham-operated-saline-injected). The administration of five 10-micrograms injections of salmon GTH on alternate days beginning in the fifth week of H resulted in a small but significant (P less than 0.05) decrease in LH-RH beyond H-saline-injected group levels (362 +/- 36 pg). The ICC analysis of H fish indicated a decrease in immunoreactive (ir)-LH-RH in the nucleus preopticus periventricularis (NPP) and nucleus lateralis tuberis pars posterioris (NLT), but a marked increase in the immunoreactivity of the neurons in the nucleus olfactoretinalis (NOR). The H fish which received GTH showed a decrease in ir-LH-RH in the NOR, but a slight increase in the NPP and NLT. The results demonstrate that although there is a general decrease in the LH-RH content of brains in H fish as determined by RIA and ICC, one of 3 ir-LH-RH-containing centers of the brain, the NOR, shows a marked increase in ICC-demonstrable LH-RH, indicating that these 3 regions may differ in their roles in the regulation of the reproductive system. The drop in RIA-measurable LH-RH in the brain, along with the enlarged perikarya observed in all 3 regions, suggests that an increase in the synthesis and release of LH-RH occurs in response to removal of the pituitary. The functional significance of the NOR and the feedback mechanisms between brain, pituitary and gonads are discussed.

Animals↗
PubMed1989

Suppression of neuropeptide Y-elicited eating by adrenalectomy or hypophysectomy: reversal with corticosterone.

Neuropeptide Y (NPY) injected into the paraventricular hypothalamus (PVN) stimulates a robust eating response in the satiated rat. To examine whether the NPY-feeding system interacts with the pituitary-adrenal axis, the eating response to PVN injections of NPY (78 pmol) was tested in adult male rats before and after sham surgery, adrenalectomy (ADX), hypophysectomy (HYPX), and/or corticosterone (CORT) replacement therapy. In unoperated or sham groups, NPY elicited 5.7-8.8 g of food intake in 1 h as compared to 0.4-1.1 g for vehicle-injected animals. In ADX groups, the NPY-elicited response was reduced by 60-71%, to between 2.4 and 2.8 g. Likewise, the average response of the HYPX group was reduced by 69%, to 1.7 g. Corticosterone replacement, via subcutaneous implant of a 100 mg CORT pellet, normalized the NPY-induced feeding response in both the ADX and HYPX groups. These findings suggest that the hypothalamic NPY-feeding system is largely dependent upon circulating CORT and that no other adrenal or pituitary hormone is essential.

Animals↗
PubMed1983

Hypophysectomy prevents yawning and penile erection but not hypomotility induced by apomorphine.

A small dose of apomorphine (25 or 50 micrograms/kg, SC) induced repeated episodes of yawning, penile erection, genital grooming and a decrease in locomotor activity in rats. Hypophysectomy almost completely abolished yawning, penile erection and genital abolished yawning, penile erection and genital grooming but failed to modify the hypomotility induced by apomorphine. These results suggest that pituitary hormones are directly or indirectly involved in the apomorphine-induced yawning, penile erection and genital grooming but not in the sedative response to this drug.

Adrenocorticotropic Hormone↗